1. Field of the Invention
The present invention relates to a massage device for a chair-type massage apparatus, more particularly to a massage device capable of performing combined tapping and kneading massaging actions.
2. Description of the Related Art
FIG. 1 illustrates a massage apparatus for mounting in the backrest of a chair. The massage apparatus includes a parallel pair of upright guiding rails 111 extending upwardly from on a horizontal platform 112, a screw rod 12 mounted rotatably on the platform 12 and extending upwardly there from and a slide seat 13 mounted on the screw rod 12 and slidable upwardly and downwardly along the guiding rails 111. A first motor 16 is mounted on the platform 112 for driving rotation of the screw rod 12. A conventional massage device 2 is mounted on the slide frame 13, and is driven by a second motor 14 mounted on the slide frame 13.
With further reference to FIG. 2, the conventional massage device 2 includes two casing halves which cooperatively form a hollow casing 21, and a rotary drive shaft 221 disposed uprightly in the hollow casing 21 and coupled to the second motor 14 by means of a pulley 17 and a transmission belt 141 disposed on the pulley 17. The drive shaft 221 is driven by the second motor 14 to rotate axially in the hollow casing 2. The casing 2 has horizontal upper and lower output shafts 231, 232 extending transversely therethrough. An upper gear set includes an upper drive gear 225 sleeved co-axially on the drive shaft 221, and an upper driven gear 233 meshing with the upper drive gear 225 and sleeved rigidly on the upper output shaft 231. A lower gear set includes a lower drive gear 226 sleeved co-axially on the drive shaft 221, and a lower driven gear 234 meshing with the lower drive gear 226 and sleeved rigidly on the lower output shaft 232. A first unidirectional bearing 223 is disposed between the drive shaft 221 and the upper drive gear 225, and is operable to transmit rotation in only a first direction. A second unidirectional bearing 224 is disposed between the drive shaft 221 and the lower drive gear 226, and is operable to transmit rotation in only a second direction opposite to the first direction. Two linkage units 24 are disposed on opposite sides of the hollow casing 21. Each linkage unit 24 has an upper linking plate 241 connected pivotally to the upper output shaft 231 at one end and mounted rotatably with a massage wheel 243 at the other end, a lower linking rod 242 with a lower end connected pivotally to the lower output shaft 232, and an upper end mounted pivotally on an intermediate portion of the linking plate 241.
When the drive shaft 221 is rotated in the first direction, the first unidirectional bearing 223 engages and rotates with the drive shaft 221 to cause corresponding rotation of the upper output shaft 231 via the upper gear set, whereas the second unidirectional bearing 224 prevents rotation of the drive shaft 221 from being transmitted to the lower gear set. Rotation of the upper output shaft 231 causes the upper linking plates 241 to move reciprocatingly to enable the massaging wheels 243 to exert a kneading massaging action on the back of a user seated on the chair that incorporates the massage device 2. On the other hand, when the drive shaft 221 is rotated in the second direction, the second unidirectional bearing 224 engages and rotates with the drive shaft 221 to cause corresponding rotation of the lower output shaft 232 via the lower gear set, whereas the first unidirectional bearing 223 prevents rotation of the drive shaft 221 from being transmitted to the upper gear set. Rotation of the lower output shaft 232 causes the lower linking rod 242 to move reciprocatingly and to push and pull the upper linking plate 241 so as to enable the massaging wheels 243 to exert a tapping massaging action on the back of the user. It is noted that the tapping massaging action and the kneading massaging action are performed separately by driving the drive shaft 221 to rotate in opposite directions. When performing the tapping massaging action, each of the massaging wheels 243 taps at a certain area on the back of the user, and thus moves along a linear route during upward or downward sliding of the slide frame 13 along the guiding rails 111, as shown in FIG. 3. It is desirable to diversify the massaging action performed by the massage device and to expand the area on which the massaging action is exerted.
Therefore, the main object of the present invention is to provide a massage device capable of performing combined tapping and kneading massaging actions.
Accordingly, the massage device of the present invention includes a hollow casing, a drive shaft, parallel upper and lower output shafts, upper and lower gear sets, a unidirectional bearing, a pair of linkage units, and a pair of massaging wheels. The drive shaft is disposed uprightly in the hollow casing, and is rotatable axially in opposite first and second directions. The upper and lower output shafts are disposed transversely in the hollow casing, and have opposite end portions that extend out of the hollow casing and that are disposed respectively on opposite lateral sides of the hollow casing. The upper gear set includes an upper drive gear sleeved rigidly on the drive shaft so as to be co-rotatable with the drive shaft in the first and second directions, and an upper driven gear meshing with the upper drive gear and connected rigidly to the upper output shaft so as to permit rotation of the upper output shaft together with the drive shaft when the drive shaft rotates in each of the first and second directions. The lower gear set includes a lower drive gear disposed coaxially on the drive shaft below the upper drive gear, and a lower driven gear meshing with the lower drive gear and connected rigidly to the lower output shaft. The unidirectional bearing is provided on the drive shaft, and is disposed between the drive shaft and the lower drive gear. The unidirectional bearing prevents rotation of the drive shaft from being transmitted to the lower output shaft when the drive shaft rotates in the first direction, and permits rotation of the drive shaft to be transmitted to the lower output shaft via the lower gear set when the drive shaft rotates in the second direction. The linkage units are disposed respectively on the lateral sides of the hollow casing, and are mounted on the end portions of the upper and lower output shafts. The massaging wheels are mounted respectively on the linkage units.